Resin materials, especially transparent resin materials represented by polycarbonate and the like have such characteristics as low specific gravity, low weight, easy processibility, and better impact resistance compared with inorganic glass, and therefore are widely used in various applications. To the contrary, a resin material has disadvantages, such as, the surface thereof is easily damaged and the gloss or transparency is easily lost, it is easily invaded by organic solvents, and its weather resistance (for example, light stability with regard to rays such as ultraviolet rays) and heat resistance are poor, etc. Therefore, resin materials are usually used so as to be covered by various protective films in order to improve the surface properties thereof.
As such protective films, for example, a hard coating layer obtained by curing a light-curing coating agent composition may be exemplified.
Resin materials to be used outdoors require abrasion resistance as well as both excellent weather resistance. As a light-curing coating agent composition having both abrasion resistance and weather resistance, a composition for forming an abrasion-resistant coating is known (patent document 1), which contains colloidal silica particles whose surfaces are modified with a silane compound having a methacryloyloxy group, an acryloyloxy group or a vinyl group in predetermined proportion by weight, a monomer mixture comprising a poly[(meth)acryloyloxyalkyl]isocyanurate and a urethane (poly)methacrylate having an alicyclic skeleton, and a photopolymerization initiator, in a specific proportion.
Furthermore, a coating agent composition is also known (patent document 2), which contains, in specific proportion, a poly(meth)acrylate of mono- or poly-pentaerythritol, a urethane poly(meth)acrylate having at least two radical polymerizable unsaturated double bonds, a poly[(meth)acryloyloxyacryl](iso)cyanurate, an ultraviolet absorber, a hindered amine based light stabilizer and a photopolymerization initiator.
There is also an example in which a thermocuring coating agent composition is used. In patent document 3, a plastic article is disclosed, wherein the plastic article comprises, on a surface thereof, a first layer formed by curing a thermocuring undercoating composition having an excellent weather resistance, and a second layer on the first layer formed by curing a thermocuring coating agent composition having an excellent abrasion resistance.